The intracellular transport of proteins, lipids, and mRNA to specific locations within the cell, as well as the proper alignment and separation of chromosomes in dividing cells, is essential to the functioning of the cell. The superfamily of proteins called kinesins (KIF), along with the myosins and dyneins, function as molecular engines to bind and transport vesicles and organelles along microtubules with energy supplied by ATP. KIFs have been identified in many species ranging from yeast to humans. The amino acid sequences which comprise the motor domain are highly conserved among eukaryotic phyla, while the region outside of the motor domain serves to bind to the cargo and varies in amino acid sequence among KIFs. The movement of a kinesin along a microtubule can occur in either the plus or minus direction, but any given kinesin can only travel in one direction, an action that is mediated by the polarity of the motor and the microtubule. The KIFs have been grouped into three major types depending on the position of the motor domain: the amino-terminal domain, the middle motor domain, and the carboxyl-terminal domain, referred to respectively as N-kinesin, M-kinesin, and C-kinesins. These are further classified into 14 classes based on a phylogenetic analysis of the 45 known human and mouse kinesin genes (Miki et al., Proc. Natl. Acad. Sci. U.S.A., 2001, 98, 7004-7011).
One such kinesin, kinesin-like 1, a member of the N-2 (also called bimC) family of kinesins and is involved in separating the chromosomes by directing their movement along microtubules in the bipolar spindle. During mitosis, the microtubule bipolar spindle functions to distribute the duplicated chromosomes equally to daughter cells. Kinesin-like 1 is first phosphorylated by the kinase p34cdc2 and is essential for centrosome separation and assembly of bipolar spindles at prophase (Blangy et al., Cell, 1995, 83, 1159-1169). In rodent neurons, kinesin-like 1 is expressed well past their terminal mitotic division, and has been implicated in regulating microtubule behaviors within the developing axons and dendrites (Ferhat et al., J. Neurosci., 1998, 18, 7822-7835). The gene encoding human kinesin-like 1 (also called KNSL1, Eg5, HsEg5, HKSP, KIF11, thyroid interacting protein 5, and TRIPS) was cloned in 1995 (Blangy et al., Cell, 1995, 83, 1159-1169).
Inhibition of kinesin-like 1 has been suggested as a target for arresting cellular proliferation in cancer because of the central role kinesin-like 1 holds in mitosis. Expression of kinesin-like 1 may also contribute to other disease states. A contribution of kinesin-like 1 to B-cell leukemia has been demonstrated in mice as a result of upregulated expression of kinesin-like 1 following a retroviral insertion mutation in the proximity of the kinesin-like 1 gene (Hansen and Justice, Oncogene, 1999, 18, 6531-6539). Autoantibodies to a set of proteins in the mitotic spindle assembly have been detected in human sera and these autoantibodies have been associated with autoimmune diseases including carpal tunnel syndrome, Raynaud's phenomenon, systemic sclerosis, Sjorgren's syndrome, rheumatoid arthritis, polymyositis, and polyarteritis. One of these autoantigens is kinesin-like 1 and has been identified in systemic lupus erythematosus (Whitehead et al., Arthritis Rheum., 1996, 39, 1635-1642).
Currently, there are no known therapeutic agents which effectively inhibit the synthesis of kinesin-like 1. The use of antibodies to kinesin-like 1 has been reported several times in the art as a method to examine the participation of kinesin-like 1 during different stages of mitosis (Blangy et al., Cell, 1995, 83, 1159-1169.; Kapoor et al., J. Cell Biol., 2000, 150, 975-988.; Whitehead and Rattner, J. Cell Sci., 1998, 111, 2551-2561). For instance, in the presence of antibodies specific to kinesin-like 1, microtubule arrays responsible for pre- and post-mitotic centrosome movement never form, confirming the recurring role of kinesin-like 1 in establishing the microtubule arrays that form during cell division. This role may also encompass the ability of kinesin-like 1 to influence the distribution of other protein components associated with cell division (Whitehead and Rattner, J. Cell Sci., 1998, 111, 2551-2561).
The small molecule monastrol has been used in vitro as a useful and specific tool to probe the involvement of kinesin-like 1 in the mitotic process (Kapoor et al., J. Cell Biol., 2000, 150, 975-988). Like the anti-kinesin-like 1 antibodies, the small molecule monastrol produces a monoastral phenotype, as opposed to the bipolar spindle, and subsequently arrests mitosis. The formation of the monastral spindle is reversible when monastrol is washed away, and the mechanism of monastrol action is presumed to be inhibition of kinesin-like 1 (Mayer et al., Science, 1999, 286, 971-974).
Another small molecule, all-trans-retinoic acid (ATRA) is able to arrest growth in a number of different cell types such as melanoma, lymphoma, neuroblastoma, embryonic stem, and carcinoma cells by modulating gene expression. Kinesin-like 1 is one of these target genes and the expression of kinesin-like 1 in pancreatic carcinoma cell lines is inhibited by ATRA at the posttranscriptional level. These anti-proliferative effects arising from ATRA inhibition of kinesin-like 1 was further confirmed by the use of an antisense expression vector directed against kinesin-like 1 (Kaiser et al., J. Biol. Chem., 1999, 274, 18925-18931).
U.S. Patent Application Publication No. 2002/0165240, published Nov. 7, 2002 (Kimball et al.), discloses methods for treating a condition via modulation of Eg5 protein activity comprising administering a small molecule Eg5 inhibitor.
There remains a long felt need for additional agents capable of effectively inhibiting kinesin-like 1 function.
Antisense technology is emerging as an effective means for reducing the expression of specific gene products and may therefore prove to be uniquely useful in a number of therapeutic, diagnostic, and research applications for the modulation of kinesin-like 1 expression. A small interfering RNA (siRNA) targeting the mRNA of the kinesin has been used to assay for the optimization of siRNA transfection, and was found to induce mitotic arrest. D. Weil et al., 2002, BioTechniques 33:1244-1248. U.S. Pat. No. 6,472,521, issued Oct. 29, 2002 (Uhlmann et al.), discloses and claims oligonucleotides for the inhibition of human Eg5 expression. PCT Publication WO 03/030832, published Apr. 17, 2003 (Reinhard et al.), discloses use of antisense oligonucleotides that target human kinesin genes for treating diseases involving aberrant cell proliferation. The kinesin gene may be human Eg5.
The present invention provides compositions and methods for modulating kinesin-like 1 expression.